What does it mean " instantaneous power" ???
HB simulations will give you the peak power of a system output when the system is settled down.It's also valid for the oscillators.When an oscillator starts to oscillate, a certain time should be passed to it settled down and then output power will be constant by time.( if the OSC is well designed.) But this power can be very variable by temperature and loading charge.
Average power might be needed when the load is complex.
Instantaneous power is obtained by transient simulation in any time slot but useless...
ALL HB based simulators wait the system reaching steady state then they simulate power, frequency,PN etc..